Textbook Question
Assume you have a 10-lb weight in your right hand. Explain why it is easier to flex the right elbow when your forearm is supinated than when it is pronated.
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Ch. 10 The Muscular System
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732
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Table of contents
- Ch. 1 The Human Body: An Orientation25
- Ch. 2 Chemistry Comes Alive24
- Ch. 3 Cells: The Living Units24
- Ch. 4 Tissue: The Living Fabric19
- Ch. 5 The Integumentary System12
- Ch. 6 Bones and Skeletal Tissues19
- Ch. 7 The Skeleton14
- Ch. 8 Joints7
- Ch. 9 Muscles and Muscle Tissue26
- Ch. 10 The Muscular System25
- Ch. 11 Fundamentals of the Nervous System and Nervous Tissue23
- Ch. 12 The Central Nervous System25
- Ch. 13 The Peripheral Nervous System and Reflex Activity30
- Ch. 14 The Autonomic Nervous System16
- Ch. 15 The Special Senses26
- Ch. 16 The Endocrine System26
- Ch. 17 Blood27
- Ch. 18 The Cardiovascular System: The Heart25
- Ch. 19 The Cardiovascular System: Blood Vessels27
- Ch. 20 The Lymphatic System and Lymphoid Organs and Tissues16
- Ch. 21 The Immune System: Innate and Adaptive Body Defenses27
- Ch. 22 The Respiratory System21
- Ch. 23 The Digestive System31
- Ch. 24 Nutrition, Metabolism, and Energy Balance26
- Ch. 25 The Urinary System26
- Ch. 26 Fluid, Electrolyte, and Acid-Base Balance24
- Ch. 27 The Reproductive System24
- Ch. 28 Pregnancy and Human Development25
- Ch. 29 Heredity11
Hoehn, Haynes, Abbott12th EditionMarieb Human Anatomy & PhysiologyISBN: 9780138242732Not the one you use?Change textbook
Chapter 10, Problem 25
Mr. Ahmadi, an out-of-shape 45-year-old man, was advised by his physician to lose weight and to exercise on a regular basis. He followed his diet faithfully and began to jog daily. One day, while on his morning jog, he heard a snapping sound that was immediately followed by a severe pain in his right lower calf. When his leg was examined, a gap was seen between his swollen upper calf region and his heel, and he was unable to plantar flex that ankle. What do you think happened? Why was the upper part of his calf swollen?
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Step 1: Identify the anatomical structures involved based on the symptoms. The inability to plantar flex the ankle and the gap between the upper calf and heel suggest an injury to the Achilles tendon, which connects the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus).
Step 2: Understand the mechanism of injury. A snapping sound followed by severe pain during jogging indicates a sudden rupture or tear of the Achilles tendon, which commonly occurs in middle-aged individuals who are not regularly active.
Step 3: Explain why the upper part of the calf is swollen. When the Achilles tendon ruptures, the calf muscles lose their attachment to the heel and retract upwards, causing a visible gap and swelling due to muscle retraction and localized bleeding or inflammation.
Step 4: Correlate the functional deficit with the injury. Since the Achilles tendon is essential for plantar flexion (pointing the foot downward), its rupture results in the inability to perform this movement, which is why Mr. Ahmadi cannot plantar flex his ankle.
Step 5: Summarize the clinical diagnosis. Based on the history, physical findings, and functional loss, the most likely diagnosis is an Achilles tendon rupture with associated muscle retraction and swelling in the upper calf.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Achilles Tendon Rupture
An Achilles tendon rupture occurs when the strong tendon connecting the calf muscles to the heel bone tears, often causing a snapping sound and sudden pain. It typically results from sudden, forceful movements, especially in middle-aged or inactive individuals starting exercise. This injury leads to difficulty or inability to plantar flex the foot, as the tendon is essential for pushing off the ground.
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3:01
Tendon Reflex
Calf Muscle Anatomy and Function
The calf is primarily composed of the gastrocnemius and soleus muscles, which merge into the Achilles tendon attaching to the heel. These muscles contract to plantar flex the foot, enabling activities like walking and jogging. When the Achilles tendon ruptures, the calf muscles lose their anchor, causing the muscle belly to retract and form a visible gap and swelling in the upper calf.
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06:04Functional Groups
Clinical Signs of Tendon Injury
Key clinical signs of an Achilles tendon rupture include a palpable gap above the heel, swelling, bruising, and inability to plantar flex the ankle. The swelling in the upper calf is due to muscle retraction and localized bleeding or inflammation. Recognizing these signs helps differentiate tendon rupture from other calf injuries like muscle strains or deep vein thrombosis.
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3:01Tendon Reflex
Related Practice
Textbook Question
As Kendra's coach watched her sail over the high jump bar, he contracted his right orbicularis oculi muscle, raised his arm, and contracted his opponens pollicis. Was he pleased or displeased with her performance? How do you know?
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Textbook Question
When Mrs. O'Brien returned to her doctor for a follow-up visit after childbirth, she complained that she was incontinent (having problems controlling her urine flow) when she sneezed. The physician asked his nurse to give Mrs. O'Brien instructions on how to perform exercises to strengthen the muscles of the pelvic floor. To which muscles was he referring?
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Textbook Question
What class of lever system do the following activities describe?
a. The soleus muscle plantar flexes the foot.
b. The triceps brachii is strained while doing pushups.
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